1/*
2 * AppArmor security module
3 *
4 * This file contains AppArmor capability mediation functions
5 *
6 * Copyright (C) 1998-2008 Novell/SUSE
7 * Copyright 2009-2010 Canonical Ltd.
8 *
9 * This program is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU General Public License as
11 * published by the Free Software Foundation, version 2 of the
12 * License.
13 */
14
15#include <linux/capability.h>
16#include <linux/errno.h>
17#include <linux/gfp.h>
18
19#include "include/apparmor.h"
20#include "include/capability.h"
21#include "include/context.h"
22#include "include/policy.h"
23#include "include/audit.h"
24
25/*
26 * Table of capability names: we generate it from capabilities.h.
27 */
28#include "capability_names.h"
29
30struct aa_fs_entry aa_fs_entry_caps[] = {
31	AA_FS_FILE_STRING("mask", AA_FS_CAPS_MASK),
32	{ }
33};
34
35struct audit_cache {
36	struct aa_profile *profile;
37	kernel_cap_t caps;
38};
39
40static DEFINE_PER_CPU(struct audit_cache, audit_cache);
41
42/**
43 * audit_cb - call back for capability components of audit struct
44 * @ab - audit buffer   (NOT NULL)
45 * @va - audit struct to audit data from  (NOT NULL)
46 */
47static void audit_cb(struct audit_buffer *ab, void *va)
48{
49	struct common_audit_data *sa = va;
50	audit_log_format(ab, " capname=");
51	audit_log_untrustedstring(ab, capability_names[sa->u.cap]);
52}
53
54/**
55 * audit_caps - audit a capability
56 * @profile: profile being tested for confinement (NOT NULL)
57 * @cap: capability tested
58 * @error: error code returned by test
59 *
60 * Do auditing of capability and handle, audit/complain/kill modes switching
61 * and duplicate message elimination.
62 *
63 * Returns: 0 or sa->error on success,  error code on failure
64 */
65static int audit_caps(struct aa_profile *profile, int cap, int error)
66{
67	struct audit_cache *ent;
68	int type = AUDIT_APPARMOR_AUTO;
69	struct common_audit_data sa;
70	struct apparmor_audit_data aad = {0,};
71	sa.type = LSM_AUDIT_DATA_CAP;
72	sa.aad = &aad;
73	sa.u.cap = cap;
74	sa.aad->op = OP_CAPABLE;
75	sa.aad->error = error;
76
77	if (likely(!error)) {
78		/* test if auditing is being forced */
79		if (likely((AUDIT_MODE(profile) != AUDIT_ALL) &&
80			   !cap_raised(profile->caps.audit, cap)))
81			return 0;
82		type = AUDIT_APPARMOR_AUDIT;
83	} else if (KILL_MODE(profile) ||
84		   cap_raised(profile->caps.kill, cap)) {
85		type = AUDIT_APPARMOR_KILL;
86	} else if (cap_raised(profile->caps.quiet, cap) &&
87		   AUDIT_MODE(profile) != AUDIT_NOQUIET &&
88		   AUDIT_MODE(profile) != AUDIT_ALL) {
89		/* quiet auditing */
90		return error;
91	}
92
93	/* Do simple duplicate message elimination */
94	ent = &get_cpu_var(audit_cache);
95	if (profile == ent->profile && cap_raised(ent->caps, cap)) {
96		put_cpu_var(audit_cache);
97		if (COMPLAIN_MODE(profile))
98			return complain_error(error);
99		return error;
100	} else {
101		aa_put_profile(ent->profile);
102		ent->profile = aa_get_profile(profile);
103		cap_raise(ent->caps, cap);
104	}
105	put_cpu_var(audit_cache);
106
107	return aa_audit(type, profile, GFP_ATOMIC, &sa, audit_cb);
108}
109
110/**
111 * profile_capable - test if profile allows use of capability @cap
112 * @profile: profile being enforced    (NOT NULL, NOT unconfined)
113 * @cap: capability to test if allowed
114 *
115 * Returns: 0 if allowed else -EPERM
116 */
117static int profile_capable(struct aa_profile *profile, int cap)
118{
119	return cap_raised(profile->caps.allow, cap) ? 0 : -EPERM;
120}
121
122/**
123 * aa_capable - test permission to use capability
124 * @profile: profile being tested against (NOT NULL)
125 * @cap: capability to be tested
126 * @audit: whether an audit record should be generated
127 *
128 * Look up capability in profile capability set.
129 *
130 * Returns: 0 on success, or else an error code.
131 */
132int aa_capable(struct aa_profile *profile, int cap, int audit)
133{
134	int error = profile_capable(profile, cap);
135
136	if (!audit) {
137		if (COMPLAIN_MODE(profile))
138			return complain_error(error);
139		return error;
140	}
141
142	return audit_caps(profile, cap, error);
143}
144